Facilitating Hot Electron Injection from Graphene to Semiconductor by Rectifying Contact for Vis–NIR‐Driven H2O2 Production

Abstract Solar‐driven production of hydrogen peroxide (H 2 O 2 ), as an important industrial chemical oxidant with an extensive range of applications, from oxygen reduction is a sustainable alternative to mainstream anthraquinone oxidation and direct hydrogenation of dioxygen methods. The efficiency of solar to hydrogen peroxide over semiconductor‐based photocatalysts is still largely limited by the narrow light absorption to visible light. Here, the authors proposed and demonstrate the proof‐of‐concept application of light‐generated hot electrons in a graphene/semiconductor (exemplified with widely used TiO 2 ) dyad to largely extend visible light spectra up to 800 nm for efficient H 2 O 2 production. The well‐designed graphene/semiconductor heterojunction has a rectifying interface with a zero barrier for the hot electron injection, largely boosting excited hot electrons with an average lifetime of ≈0.5 ps into charge carriers with a long fluorescent lifetime (4.0 ns) for subsequent H 2 O 2 production. The optimized dyadic photocatalyst can provide an H 2 O 2 yield of 0.67 m m g –1 h –1 under visible light irradiation (λ ≥ 400 nm), which is 20 times of the state‐of‐the‐art noble‐metal‐free titanium oxide‐based photocatalyst, and even achieves an H 2 O 2 yield of 0.14 m m g –1 h –1 upon photoexcitation by near‐infrared‐region light (≈800 nm).